U.S. Pat. No. 3,079,096, entitled "Crushing Apparatus" issued Feb. 26, 1963 to David P. McConnell, father of the inventor herein. The crusher described and claimed in that patent is particularly representative of the prior art with respect to the present invention and is accordingly discussed in greater detail below. The jaw crusher of the present invention includes certain features in common with the apparatus of the above patent and also in common with a copending U.S. patent application, Ser. No. 06/943,548; filed Dec. 18, 1986 and entitled "Improved Jaw Crusher with Drop-In Jaw" invented by Laurence U. Turly and David P. McConnell, also the inventor herein.
Accordingly, both U.S. Pat. No. 3,079,096 and the copending application referred to above are incorporated herein as though set forth in their entirety in order to provide a more complete understanding of the present invention, particularly as to common crushing apparatus features.
The crushing apparatus of the present invention also includes certain features in common with apparatus disclosed in another copending U.S. patent application, Ser. No. 06/823,309; filed Jan. 28, 1986 by David P. McConnell, the inventor herein, entitled "Jaw Crushing Apparatus" and now assigned to the assignee of the present invention. Accordingly, that copending and commonly owned reference is also incorporated herein as though set forth in its entirety.
Referring now to the incorporated references, U.S. Pat. No. 3,079,096 disclosed a jaw crusher of the type generally referred to above wherein an eccentric mass was supported for rotation behind each of its opposed jaws. Substantial forces acting upon the jaws were absorbed by resilient means including wheels with pneumatic tires arranged in shoes or cylindrical tracks partially surrounding the tires. In addition to absorbing tremendous shock loading on the jaws, the resilient tires permitted the jaws to move away from each other as necessary when uncrushable material formed, for example, from hardened steel or the like, entered between the jaws.
Accordingly, the jaw crusher of the reference was particularly effective in crushing materials such as rock while preventing the jaws or other portions of the crusher from being damaged by uncrushable material passing between the jaws.
Other jaw crushers including vibratory jaw crushers with opposed jaws operated by rotating eccentric masses have also been disclosed in the prior art. For example, reference is made to U.S. Pat. No. 1,247,701 issued Nov. 27, 1917 to Michaelsen. However, at least for purposes of the present invention, these other prior art jaw crushers are believed to be generally equivalent to that of the above incorporated reference.
Although the prior art jaw crushers discussed above were very effective for their purpose, it has been found desirable to further improve their design for further enhancing jaw crusher operation in a variety of applications. Particularly in connection with large size crushers adapted for crushing large rocks or the like, some difficulty has been found in assuring uniform transmission of oscillatory motion to different parts of the jaws. For example, when large rocks are the like which are difficult to crush are trapped between certain portions of the opposed jaws, vibratory forces applied to the jaws follow the path of least resistance so that the jaws tend to experience increased vibratory movement at a location away from the large rock. This tendency naturally interferes with rapid and efficient crusher operation.
In addition, difficulty has also been encountered in assuring uniform transmission of vibratory motion to jaws of increased size. This is true both for jaws of extended or increased lateral dimension, for example, to achieve increased throat size, or increased longitudinal dimension, for example where a longer, more gradual nip is desired between the jaws.
It has also been noted that, particularly with larger crushers, assembly and disassembly is made more difficult. This is most noticeable in connection with the jaws themselves which tend to experience concentrated wear during operation of the crusher.
Accordingly, there has been found to remain a need for a jaw crusher exhibiting improvements in the areas discussed above as well as in other areas.